The present invention generally relates to a reusable personal heating system filled with a supercooled supersaturated solution and including a trigger device and to a garment worn under other clothing containing a removable and reusable personal heating system easily accessible through other clothing.
It is beneficial for people participating in outdoor activities such as diving, motorcycle riding, hunting, fishing, water skiing, snow skiing, yard work, etc. to wear light-weight clothing which allows for ease of mobility and range of motion. During some of these activities the participant becomes wet or is submerged in water for all or most of the time. Some of these activities are done in cool weather. As a result, the participant is forced to wear heavier clothing or multiple layers, hence restricting his mobility and motion. This may shorten his time spent participating in the activity. For example, when diving in colder environments, the diver may wear a thicker wet suit. Another option is to purchase a dry suit, but they are expensive and require additional training to operate safely. Electric heaters are available for dry suits, but most are expensive and not easily recharged.
There are many heat packs utilizing a supercooled, supersaturated solution and a metallic activator to educe an exothermic phase change and warm the user. The solution and activator are stored inside a container, usually a plastic pouch, such that the solution is in contact with the activator. When the metallic activator is flexed, it initiates the crystallization process and heat is released. Once the crystallization process is complete, the container is heated, for example by boiling, melting the solution once more. After the solution is melted, the activator can be flexed again, starting the process over. For more information on how the metallic activator initiates the crystallization process, see Mansel A. Rogerson & Silvana S. Cardoso, Solidification in Heat Packs: III. Metallic Trigger, Vol. 49, No. 2 AICHE JOURNAL 522 (Feb. 2003).
These heat packs are reliable, inexpensive, environmentally safe and easily recharged; however, the commercially available heat packs are not suitable to be activated under layers of clothing. For one thing, the heat packs are hard to access through multiple layers and, therefore, difficult to activate. Many of these heat packs require two hands to activate. Additionally, often the activator floats in the solution making it difficult to locate. As a result, the user must activate the heat pack before inserting it under layers of clothing in order to use it during diving or other such activity. It is desirable to activate the heat pack after spending some time participating in the activity, for example, when a diver descends into a colder depth of water.